<template>
  <div>
      <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
        <div class="iconfont header-abs-back">&#xe624;</div>
      </router-link>
      <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
        <router-link to="/">
          <div class="iconfont header-fixed-back">&#xe624;</div>
        </router-link>
          景点详情
      </div>
  </div>
</template>

<script>

export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      // console.log('scroll')
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    //   console.log(document.documentElement.scrollTop)
    }
  },
  mounted () {
    // 全局事件解绑
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
    @import '~styles/variable.styl'
    .header-abs
      position absolute
      left .2rem
      top .2rem
      width .8rem
      height .8rem
      line-height .8rem
      border-radius .4rem
      text-align center
      background rgba(0, 0, 0, .8)
      .header-abs-back
        color #fff
        font-size .4rem
    .header-fixed
      z-index 2
      position fixed
      top 0
      left 0
      right 0
      height $headerHeight
      line-height $headerHeight
      // overflow hidden
      text-align center
      color #fff
      background $bgColor
      font-size .32rem
      .header-fixed-back
        position absolute
        top 0
        left 0
        width .64rem
        font-size .4rem
        text-align center
        color #fff
</style>
